I feel I should include an explanation for the lack of Xref talk so far, I've not unintentionally overlooked them. To put it simply: they just don't work for me.
I expect a large percentage of people are using Xrefs without an problem; perhaps locally rather than over a server, or in scenes that aren't so heavy, I have no doubt they serve a purpose to some. I also know I'm not alone in avoiding them. I give Xrefs one really fair chance in a project ever new release and so far they have caused more trouble then it was worth. Wonky PSR glitches, painfully slow texture loading, serious scene corruption (save incrementally, often), infecting other scenes with 'ghost' elements that cannot be removed.
The idea is fantastic: keep objects in a separate files to work on as a team then create a reference to that in another file. Animate, deform, texture, it sounds like a dream but in reality my project files feel like they are held together by a thread that could snap at any second... when the metaphor for your scene file becomes parallel with the metaphor for your nerves at the end of a project then you have a problem.
I cannot implore you to never use them, I will not say they do not work at all, but I cannot honestly recommend them for most things. Please try them out and see if they work for you.